Windows Memory Reduction at Boot Time by Memory Page Reset to Zero for Virtual Machine

1. A method for zeroing guest memory of a Virtual Machine (VM) during boot up, the method comprising: (a) setting a host memory page to zero; (b) issuing a command to set a first guest memory page to zero; (c) waiting for a page fault in the Virtual Machine and transferring the page fault to a supervisory component running on a host node; (d) mapping the first guest memory page to the host memory page; (e) giving the host memory page to the VM to correspond to the first guest memory page; (f) in the VM, setting the first guest memory page to zero; (g) issuing a command to set a second guest memory page to zero; (h) waiting for a second page fault and transferring the second page fault to the supervisory component; (i) unmapping the first guest memory page from the host memory page; (j) mapping the second guest memory page to the host memory page; (k) giving the host memory page to the VM to correspond to the second guest memory page; (l) in the VM, setting the second guest memory page to zero; and (m) repeating steps (g) though (l) for remaining pages of the guest memory, wherein the steps (a)-(m) are performed during boot up of the VM.

2. The method of claim 1 , wherein the supervisory component, in step (i), first checks if the host memory page is already mapped to the VM.

3. The method of claim 1 , wherein step (m) is repeated until a predetermined counter value of the first guest memory page being non-zero is reached.

4. The method of claim 1 , wherein steps (a-m) are repeated for a different VM.

5. The method of claim 4 , wherein the host memory page is shared for both VMs.

6. The method of claim 1 , wherein multiple VMs are launched on the host, and each VM has its own host memory page that is not shared with other VMs.

7. The method of claim 1 , wherein the VM has multiple host memory pages, and wherein the steps (a)-(m) are repeated for all the multiple host memory pages.

8. A system for zeroing guest memory of a Virtual Machine (VM) during boot up, the system comprising: (a) a hardware processor running a host operating system (OS); (b) a host memory page set to zero; (c) a guest OS of a Virtual Machine (VM) that issues a command to set a first guest memory page to zero; (d) a supervisory component running on the processor, and to which a first page fault in the Virtual Machine that is triggered by the command is transferred; (e) wherein the first guest memory page is mapped to the host memory page; (f) the supervisory component is configured to give the host memory page to the VM to correspond to the first guest memory page; (g) the VM is configured to set the first guest memory page to zero; (h) the guest OS is configured to issue a second command to set a second guest memory page to zero; (i) the supervisory component is configured to process the second page fault triggered by the second command; (j) the supervisory component is configured to unmap the first guest memory page from the host memory page, and to map the second guest memory page to the host memory page; (k) the supervisory component is configured to give the host memory page to the VM to correspond to the second guest memory page; (l) the VM is configured to set the second guest memory page to zero; and (m) wherein the supervisory component is configured to repeat (i)-(l) for remaining pages of the guest memory, and, (n) wherein (c)-(m) are performed during boot up of the VM.

9. The system of claim 8 , wherein the supervisory component is configured to first check if the host memory page is already mapped to the VM.

10. The system of claim 8 , wherein (m) is repeated until a predetermined counter value of the first guest memory page being non-zero is reached.

11. The system of claim 8 , wherein the supervisory component repeats the process for a different VM.

12. The system of claim 11 , wherein the host memory page is shared for both VMs.

13. The system of claim 8 , wherein multiple VMs are launched on the host, and each VM has its own host memory page that is not shared with other VMs.

14. The system of claim 8 , wherein the VM has multiple host memory pages, and wherein (a)-(m) are repeated for all the multiple host memory pages.